Rifampin, also known as rifampicin, is a semisynthetic macrocyclic bactericidal antibiotic derived from Amycolatopsis mediterranei. Rifampin inhibits DNA-dependent RNA polymerase activity through interaction with bacterial RNA polymerase. Rifampin is used in the treatment of mycobacterium infections and may be used in combination with fusidic acid in the treatment of methicillin-resistant Staphylococcus aureus (MRSA). In addition, rifampin, in combination with other drugs, is used to treat infection by Listeria species, Haemophilus influenzae, Neisseria gonorrhoeae, and Legionella pneumophila. 
Further, rifampin, in combination with minocycline, has been incorporated into polymeric implantable medical devices, such as catheters, to reduce the risk of infection associated with implantation of the devices. Many of these rifampin-containing implantable medical devices are sterilized via treatment with ethylene oxide (EtO).